fread() on a bad disk?

[annied]

Hi all, my program does the following:

mbr = fopen(fullpath, "r");
if (!mbr) {
fprintf(stderr, "VxVM ERROR V-5-3-000: Can't open device %s
\n",
fullpath);
return 0;
}

count = fread(buffer, 1, 512, mbr);
if (count < 512) {
return and print error
}


the problem is when a disk has been pulled from the system, my call to fread() on linux never returns, it just hangs (got this from gdb debugger).

Any ideas???

[Extremist]

Hi all, my program does the following:

mbr = fopen(fullpath, "r");
if (!mbr) {
fprintf(stderr, "VxVM ERROR V-5-3-000: Can't open device %s
\n",
fullpath);
return 0;
}

count = fread(buffer, 1, 512, mbr);
if (count < 512) {
return and print error
}


the problem is when a disk has been pulled from the system, my call to fread() on linux never returns, it just hangs (got this from gdb debugger).

Any ideas???

mbr = fopen(fullpath, "r");
        if (!mbr) {
                fprintf(stderr, "VxVM ERROR V-5-3-000: Can't open device %s
\n",
                        fullpath);
                return 0;
        }
 
        count = fread(buffer, 1, 512, mbr);
        if (count < 512) {
                  return and print error
        }
 

Remember the code brackets

Why don't you try:

mbr.read(buffer, 512);
 

[annied]

why mbr.read() as opposed to

read(mbr, buf, sizeof(buf)) ?

will read() solve the problem of hanging? Any idea why?

[annied]

tried using read() instead. Got the same result....hang

[weaknessforcats]

fread() is part of the C file system which dates to 1972. Back then you didn't have removable disks. fread() expects the disk to be ready and waits until it is.

Being able to pop a disk in or out (Windows Plug-and-Play) required all new code for the file system so that the program could continue if the disk were removed unexpectedly.